Mechanical pilot for aeroplanes



L. B. SPERRY. MECHANICAL PILOT FOR A'EROPLANES. APPLICATION FILED APR.24. 1916. 1,324,184. Patented Dec. 9,1919.

3 SHEETS-SHEET l.

l /VVENTOR.

A AWRENCE 5. SHERRY L B. SPERRY.

MECHANICAL PILOT FOR AEROPLANES. APPLICATION FILED APR.24, 1 9I6. 1,324,134, Patented Dec. 9,1919.

3 SHEETSPSHEET 2.

L 73 r/ E //f INVENTOR. H 4 I By ZAWRE/I/CE5.$PERRY ATTORN- Y,

L. B. SPERRY. MECHANICAL PILOT FOR AEROPLANES.

APPLICATION FILED APR.24| 1916.

Patented Dec. 9, 1919.

3 SHEETS-SHEET 3- [N VE N TOR. B LA WRE/WEESPEHRY UNITED sTArEs PATENT orrroa.

LAWRENCE IB. SPERRY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPERRY GYROSCOPIl COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

Patented Dec. 9, 1919.

Application filed April 24, 1916. Serial No. 93,078.

of the so-called automatic stabilizers, by

eliminating all auxiliary control handles. In the system of control as outlined inthe copending application of Elmer A.. Sperry,

' Serial NO. 851,477, filed July 17th, 1914, the

pilot is enabled to control the machine at will while it is under the control of the gyroscope by means of an auxiliary handle or handles which shift the relative position of the contacts on the gyroscope and on the aeroplane". By my invention, I provide means. whereby the aeroplane may be controlled at will under similar circumstances by means of the usual control handles, so

- that the aviator makes the same motions whether the-machine is under automatic or manual control. Another object is to devise a reliable means for preventing the stalling of the aeroplane by automatically volplaning it when it falls below its critical speed.

' Referring to drawings in which What I now consider the preferred forms of my invention are shown: Figure 1 is a diagrammatic development of one of my systems of control. Fig. 2 is a plan viewof a portion of a servo motor, parts bein broken away to show the details thereof. Figs 3 is a section on line 3, 3, Fig. 2. Fig.4 is an end elevation of the servo motor partly in section. Figs. 5 and 5 are details of Fig. 4. Fig. 6 is a diagrannnatic development of a modified system of control. .Fig. 7 is a section of'a constructional detail of the gyroscopic unit used in this system. Fig. 8 is an end eleva- A tion thereof. Fig. 9 is a detail being a section on line 9, 9 of Fig. 7 Fig. 10 1s a detail. y v

I In the diagrammatic outlay in Fig. 1, the master governor for controlling the stability of the aeroplane isshown at 1, and consists in this instance of a gyroscope 2 mounted on a vertical spinning axis within the usual gimbal rings 3. Contacts for controlling the servo motor 4 are arranged about each axis. Said contacts'are shown as consisting of a pair of segmental contact strips 5, 6 mounted on or connected to one of gimbal rings 3, and a brush 7 on a relatively fixed portion of the aeroplane. Preferably the brush is pivotally mounted on bracket 8 so that a follow-up movement may be communicated thereto by means of a. wire 9. The above details form no part of'the present invention, however, but are set forth in detail in the aforesaid application of Elmer A Sperry and in my copending application Serial No. 87,434 for automatic pilots for aeroplanes, filed March 29th, 191

The usual manual means for controlling the elevating rudder 10 is represented at 11, while the corresponding elements for the lateral control are shown at 12, 13. Flexible members or wires connect the handle 11, rudder l0 and the servo motor 4, while this system is connected through follow-up wire 9 to the governor l. According to this invention means are provided to temporarily sever the above connections at some point so as to allow therelation between the governor and the rudder to be changed. The. change is efiected by means of the handle 11. The severance of the said connections may also, if desired, be accomplished through the same handle 11. For this purpose, I locate in the said connections a lost motion device 100 comprising a pair of drums 14 and 15.

The drum 14 is directly connected to handle 11 through wires 16. Drum 15 is connected to drum 14 only by means of a lost 'motion device which will permit a limited relative movement of drum 14, which motion is opposed between said limits by a resilient or yielding means. This connection may consist of a pin 17 secured to drum 15 and projecting through a curved slot 18 in drum 14. The pin 17 is connected to drum 14 through-a spring 19 adapted nor- 'mally to maintain the pin in the center of the slot. The slight lost motion which takes place when the aviator pushes on handle 11 is made use of to bring into action electromagnetic means hereinafter described. for temporarily disconnecting the servo motor 4 and the control rudder 10. h

For this purpose contacts 20, 21 are located upon drum 14 with which contact 22 projecting from drum 15 is adapted to cotiperate. No attempt is made in this application to show the preferred form of the mechanical details of the lost motion device, as this device is shown completely in my aforesaid copending application.

The servo motor 4: consists essentially of a continuously rotating shaft 50 driven preferably by means of a wind motor 51; and a plurality of windings 52, 53, 54, and 55, adapted to actuate clutches thereby connecting the proper control rudder with the wind motor for actuating the same. As shown, the shaft 50 drives two intermeshing pinions 27 in opposite directions (Figs. 2 and Pinion 27 drive gears 30 and 31 while pinion 26 drives gears 32 and 33, so that the gears 30, 32 and 31. 33 will be rotated in opposite directions. The winding 52 is adapted to throw the clutch disk 35 and the clutch face of gear 30 into engage ment by attracting armature 101 so that the shaft 36 on which disk 35 is mounted will be driven in the same direction as gear 30, while winding 53 is adapted to throw gear 32 and said disk into engagement whereby said shaft will be rotated in an opposite direction. The said windings52, 53 are in circuit with the contacts 5, 6 on the gyroscopic governor, while windings 5- 55 are in circuit with contacts 56 on theother axisof the gyroscope, so that whenever the aeroplane tilts the circuit is completed to cause the servo motor to right the same.

Limiting means are preferably provided for the servo motor. For this purpose gear 37, which is driven from shaft 36, may be provided with a spiral slot 38 which is adapted to move the lever 39 to make and break contacts 10, -11 when the limit of motion of the control rudder is reached. The means for disconnecting the control rudder from the master governor is represented in this figure by gear clutch 12 which is shown in the form of a gear 13 adapted to mesh with the gear 4.5L driven by said gear 37. The preferred mechanical construction for these parts is shown in Figs. 2 and. 4:, hereinafter described. A pivoted arm 42- serves to support gear 43 while the spring 46 normally holds gears 43, 44 in mesh. An electromagnet 47 is adapted. upon being excited, to

throw out said gears. Said magnet is in circuit with said contacts 20, 21, 22 on the lost motion device above described, so that as soon as the aviator pushes upon the handle 11, gears 13, -14 will be disconnected. In this form of the invention also, the. followup wires 9 leading to the brushes on the master governor from the servo motor are connected to the shaft 36 by means of a drum 45 or to some other portion of the servo motor which remains permanently coupled to the system.

The lost motion device may also be made the contacts on the gyroscope, if the aviator should desire to cut out the automatic control. For this purpose, switches 60, 61 are provided. Each switch, when the blades engage contacts 62 completes the circuits already described, but when thrown into the position Sl10W11 the contacts on the gyroscope will be cut out, and at the same time the contact points 20, 21 will be separately connected to coils 52, 53 respectively. H

The preferred .construction of servo motor is shown in Figs. 2 and l, the parts being numbered to correspond to Fig. 1. Since the two sides of the motor are duplicates they will be described together. Pinions 62 are mounted on shafts 36, which, it will be remembered carry clutch disks 35. Arms 63 are pivoted about axes 61 in line with shafts 36 and carry gears 65 which mesh with pin.- ions 62 and other pinions 66. adapted to be thrown into and out of mesh with large gears 67 by the oscillation of arms 63. The drums 68 by which the servo motor is connected through wires 70 to the rudder are mounted on gears 67. The position of arms 63 is controlled by means of links 71, which are raised and lowered by the revolution of cams 72, 72 (Figs. 5 and 5*) one of which is secured to the shaft 73 carrying crank 74, while the other is secured to the sleeve 173 forming the hub of crank 7i. Springs 75 normally hold the rollers 76 on links 71 in engagement with the cams while other springs 77 normally hold the cams in such position that gears 66 and 67 are in mesh. Solenoids 78 corresponding to electromagnets -'l7 serve to rotate the cams through rocker arms 71, when excited, so that the gears 66 and 67 are disconnected upon the initial movement of handles 11 or 13. Further movement of either handle Will serve to shift the relation of the governor and the control planes to the desired extent.

When the handle is released, the governor again assumes control and maintains the machine in the position for which it is set.

The servo motor is also preferably equipped with brakes 80 adapted to prevent the pressure of the air puffs on the control planes or rudders from reaching back into the follow-up system and governor. The brakes are normally retracted by springs 81,

but will be applied upon the excitation of the electro-magnets 82. The brake shoe is shown as acting directly on clutch disk 35. I find it desirable to so construct each brake that it is held out of engagement with said disk not only when either one or the other of coils 52, 53 are excited, but also when the entire electrical system is thrown out and the aeroplane controlled by hand. This last feature is rendered necessary by the fact that the servo motor is so connected in the control system that the parts are revolved by the movements of the aviator when the electrical system is thrown out as well as by the automatic control. For this purpose magnets 82 are provided with two differential windings 83, 84: (Fig. 1) the former being in circuit with windlngs 52, 53 while the latter is connected to the main supply. It will thus be seen that thebrake will be applied only when the main supply is on and the clutch windings are not excited, which is the condition desired, but that as soon as either of the said windings is excited, the two windings 83, 84 will neutralize each other and release the brake. A generator 150 of any suitable form may be used to supply current for the system. A switch 151 is shown in circuit with the generator so that the entire electrical system may be deenergized and the planes moved directly by hand, if desired. 4 7

Figs. 6 to 9 illustrate important modifications in the method of altering the relation between the master governor and the stabilizing vanes or rudders. In the form shown in Fig. l, the servo motor and the governor are permanently connected through followup wires 9, and the connection between the servo motor and the rudders is broken to permit the said alteration. In Figs; 6 to 9 on the other hand the servo motor and rudders are permanently coupled, while a throwout device is placed in the follow-up connections between the servo motor and the governor.

This device is preferably located adjacent the gyroscopic unit, asshown in Figs. 7 and 8, wherein 3 represents a gimbal ring and 5', 6 the reversing contacts mounted thereon. The brush '7' is mounted on a member 90 loosely mounted on shaft '91. Pivoted at 92 on one face of member 90 is a U shaped spring 93, the free ends of which are normally pressed toward said member by a spring 94. An electro-magnetic clutch face 95 is secured on shaft 91 against axial movement adjacent member 90, so that, upon excitationof the winding 96 member 90 will be drawn toward magnet 95. A plurality of pins 97 project from a plate 98 through holes in member 90 and bear against the hub of clutch magnet 95. Plate 98 is provided with flanges 98 adapted to bear against the two legs of the spring. It will thus be seen that the excitation of winding 96 will not only couple members 90 and 95 together, but will move the free ends of spring 93 away from both members, 'sincethe points of contact between the spring and plate 98 will remain stationary, and pivot 92 will move with member 90. Projecting from the support 99 of contact segments 5, 6 is a T shaped plate 105. When the clutch :is released the plate is ositioned as shown in Fig. 9, the plate'fittlng snugly between the ends of spring 93, but when the clutch parts 95 by means of a bolt 111 adjustably secured in a slot 112, which extends through a similar slot in an extension 113 of member 95.

, According to this modification, the wind ing 96 is normally energized and the two members 90 and '95 locked together. To accomplish this purpose, a relay 114 may be interposed between switch 60 and the wind- 1 ing, so that the closing of either of contacts 20 or 21 will break the circuit through the winding at 115. This will release member 90 which will be moved back under the infiuence of spring 94 acting against plate 98 through spring 93 andwill also straighten up the spring. The purpose of spring 93 and its associated parts is to centralize brush 7 with respect to contacts 5, 6. When the clutch is engaged, the brush moves, of course with member 95, and should have no connection. with the sensitive gyroscope, but when the clutch is released, preparatory to resetting the members, I find it desirable -that'the brush be brought to the neutral position between the contacts. The spring 93 automatically accomplishes both of these results, since the ends closely engage the T end of plate 105, when the clutch is released, while when it is closed the spring is moved away from said end,'as explained.

I find it desirable not only to provide means for manually shifting the relation between the governor and rudders, but also to provide an automatic means for efiecting this purpose under special conditions. More specifically I provide an automatic volplane attachment, which, when the velocity of the machine falls below the critical speed, automatically volplanes the aeroplane. As explained in my aforesaid application, an auxiliary brush is provided about the lateral axis of the gyroscope,

which is placed at the desired angle to the main brush 7, and to which connections are made when brush 7 is cut out. The means for altering these connections are quite different from my said other applicatlon however. According to this invention I make use of the fact that, when an aeroplane falls below its critical speed, not only does its velocity through the air become less thana predetermined amount, but also its angle of incidence becomes greater than a given value. I employ the latter feature according to this invention by pivoting on the aeroplane an approximately horizontal vane 121, adapted to point in the direction in a vertical plane in, which the air strikes the aeroplane. Springs 122 maybe used to maintain the vane at the normal angle of attack if desired. But as soon as the aeroplane falls below its critical speed, the aeroplane begins to fall causing the plane to tilt in a counterclockwise direction. A contact 123 is completed thereby which energizes a coil 124, operating thereby a relay 125 which throws brush 7 out of circuit and brush 120 in circuit. This means for volplaning the machine possesses quite an advantage over a velocity controlled device, since the critical speed of an aeroplane is not a constant quantity. but varies with the load it is carrying at the time, While the critical angle of attack is a constant for each aeroplane, irrespective ot' the load it is carrying, so that the control vane need never be adjusted after it is once set.

In operating an aeroplane constructed in accordance with my invention, the aviator uses the usual control handles or foot edals in the same manner, irrespeetive of tie position of switches 60, 61. If the switches are in the position shown, the control planes will be operated directly from contacts 20, 21, 20, 21 through the servo-motor, while if the switches are thrown into contact with points 62, the planes will be operated from the contacts 5, 6 and 56 on the master governor, the positions of which are under the supervision of the aviator by simply pushing on the levers 11, 13. This movement severs the connections between the 'master governor and the control rudders at some point, such as between the servo-motor and the rudders through clutch gears 13, 44 or between the servo-motor and the governor through clutch 90, 95. At the same time the said movement moves the rudders directly to the desired position, where the lever is released, allowing the governor to take up the control in the new position. If at any time the limiting value of the angle of attack is exceeded, the vane 121 will automatically volplane the machine. When the switches are in contact with neither set of contacts and the generator circuit is open, the aviator controls the planes directly.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In an automatic pilot for aeroplanes, the combination with a master governor, of a servo-motor controlled thereby, a control rudder, a manual control lever, means in terconnecting the parts already named, said means including a follow-up connection between said governor and rudder. and a device adapted to disconnect at will the follow-up connection between the control rudder and the governor, whereby said lever may be used for shifting the relation between said rudder and said governor while said parts are disconnected.

2. In an automatic pilot for aeroplanes, the combination with a master governor, of a servo-motor controlled thereby, a control rudder, a manual control lever, means inter-connecting the parts already named including a follow-up connection between said governor and rudder and a device operated by said lever adapted to disconnect the follow-up connection between the control rudder and governor and to permit said lever to shift the relation between said rudder and said governor.

3. In an automatic pilot for aeroplanes, the combination with the manual control lever and control rudder, of-a master governor, a servo-motor controlled therefrom, a lost motion device located in the connections between said lever and said rudder, a follow-up connection between .said rudder and governor, and means brought into action by said lost motion for disconnecting the follow-up connection between the rudder and the governor.

4. In an automatic pilot for aeroplanes, a servo-motor, a master governor, a follow-up connection between said motor and governor, a control rudder connected with the servo-motor, means for preventing air pressure on the rudder from reaching the governor, and means for manually operating said rudder, said first mentioned means being controlled by said last named means.

5. In an automatic pilot for aeroplanes, a servo-motor, a master governor, a followup connection between said motor and governor, a control rudder connected with the servo-motor and a brake responsive to the deenergizing of the servo-motor for preventing the air pressure on the rudder 'from reaching the governor.

6. In an electrically controlled automatic pilot for aeroplanes, a servo-motor, a master governor, a follow-up connection be tween said motor and governor, a control rudder connected with the servo-motor, a brake on the servo-motor and means adapt ed to apply the brake only when the servomotor is denergized and at the same time the electrical system is operative.

7 In an automatic pilot for aeroplanes, the combination with a pendulous device, of contacts on said device and on an adjacent contact carrying part of the aeroplane, a

servo-motor controlled therefrom, a followupconnection from the servo-motor to a memberpositionedadjacent said part, and means for coupling and uncoupling said part and said member.

8. In an automatic pilot for aeroplanes, the combination with a pendulous device, of contacts on said device and on an adjacent part of the aeroplane, a servo-motor pling and uncoupling said controlled therefrom, a follow-up connection from the servo-motor to a member positioned adjacent said part, means for couart and said member, and means for shitting the relative posltions of said part and said member when so uncoupled.

9. In an automatic pilot for aeroplanes, the combination with a pendulous device and'a manual control handle, of contacts on said device and on an adjacent part of the aeroplane, a servo-motor controlledthe're from, a follow-up connection from the servo-motor to a member positioned adjacent said part, and means for coupling and uncoupling said part and said member, whereby the relative positions of said part and member may be shifted by means of said handle.

10. In an automatic pilot for aeroplanes, the combination with a pendulous device and a manual control handle, of contacts on said device and on an adjacent part of the aeroplane, a servo-motor controlled therefrom, a follow-up connection from the servomotor to a member positioned adjacent said part, a rudder, connections between said rudder and handle, a lost motion device in the connections between the handle and the rudder, and means responsive to an initial movement of said device for uncoupling said part and said member.

11. The "combination with a gyroscope mounted for turning about an axis, a member mounted for movement about the same axis, a plurality of electric contacts mounted on said gyroscope and on said member, said contacts comprising a plurality of separated contact segments and a cooperating brush, a clutch member adapted to engage and disengage said member, means for oscillating said clutch member, and resilient means for restoring the said contacts to their neutral relation when said clutch is released.

12. The combination with a gyroscope mounted for turning about an axis, a memher mounted for movement about the same axis, a plurality of electric contacts mounted on said gyroscope and on said member, said contacts comprising a plurality of separated contact segments and a cooperating brush, a clutch member adapted to engage and disengage said member, means for oscillating said clutch member, resilient means for re storing the said contacts to their neutral relation when said clutch is released and means releasing the connection between said resilient means and the gyroscope when the clutch is engaged.

13. In an aeroplane the combination with an elevating plane of a pendulous device, a servo-motor connected with said plane, means actuated by said device for controlling said motor, a movable horizontal vane adapted to be turned in the direction ofthe angle of attack,. and means including an electrical translating device responsive to the turning through a predetermined angle for altering the relation between said means and said device, whereby the machine is antomatically volplaned.

14. The combination with an aeroplane having a manual control lever, a control rudder, a servo-motor and a pendulous device for normally controlling the servo motor, of contacts connected w'ithsaid control lever, and means for controlling from: said contacts either the servo-motor directly, or for permittingshifting the efiective relation between the pendulous device and the rudder.

15. In an aeroplane, the combination with the usual manual control devices and stabilizing planes, of an electro-magnetic servomotor, a gyroscopic pendulum, contacts controlled by said pendulum for gover ing said servo-motor, a second set of contacts operated by said manual devices for governing said servo-motor, means for rendering either one or the other of said erated by said manual devices for governing said servo-motor, means for rendering either one' or the other of said sets operative to perform the said functions, means for adjusting the relation between the pendulum contacts and the said planes, including means controlled by said contacts for severing the. connection between the pendulum contacts and the stabilizing planes.

17. In an automatic pilot for aeroplanes. the combination with a master governor, of a servo-motor controlled thereby, a control rudder connected to said motor, a follow-up connection between said rudder and governor and means for disconnecting said fol low-up connection at will.

18. In an automatic pilot for aeroplanes, a control rudder, a manual control lever and a governor connected thereto, a servo-motor controlled by said governor, a follow-up connection between said rudder and governor and means brought into action by movement of said control lever for disconnecting said follow-up connection.

19. In an aeroplane, in combination, an elevating plane, a pendulous device, a servomotor connected with said plane, means actuated by said device for. controlling said motor, a movable, normally horizontal vane adapted to be turned in the direction of the angle of attack, a circuit controller actuated by said vane and means controlled by sald circuit controller for altering the relation between said first named means and said device.

20. In an aeroplane, in combination, a pendulous device, a plurality of electrical contacts controlled by said device, a normally horizontal vane, a plurality of electrically controlled contacts, a conductor connecting each of said first mentioned contacts to a corresponding one of the other contacts,and means including said first named contacts for controlling the equilibrium of the aeroplane.

21. In an automatic pilot for aeroplanes, the combination with the manual control lever and control rudder, of a master gov-, ernor, a servo-motor controlled therefrom, a follow-up connection between said rudder and governor, means brought into act-ion by operation of said lever for disconnecting the follow-up connection between the rudder and the governor and means for controlling said servo-motor directly from said lever.

22. In an'aeroplane, in combination, a stabilizing plane, a manually operated lever for operating the same, a servo-motor, a pendulum, contacts controlled by said pendulum for governing said servo-motor, a second set of contacts operated by said lever, connections between said second set of con-- tacts and said servo-motor, a switch for rendering said first-named contacts inefl'ec tive to control said servo-motor, a followup connection between the plane and said first-named contacts-means for disconnecting said follow-up connection and electrical connections between said second set of contacts and said last named means.-

23. In an aeroplane, in combination, a stabilizing plane, a pendulum, contacts controlled by saidpendulum, a servo-motor, a

follow-up connection between said stabilizing plane and said contacts, electrically operated means for connecting and disconnecting said follow-up connection, a manually operated lever, electrical connections between certain of said contacts and said servo motor, contacts controlled by said lever, electrical connections between certain of said last mentioned contacts and said servomotor and means for controlling said elec trically operated means from said lever.

24. The combination with an aeroplane having a manual control lever, a control rudder, a servo-motor and a pendulous device for normally controlling the servo-motor, of contacts connected. with said control lever, means including said contacts for controlling the servo-motor from said lever, .and means, also including said contacts, for shifting the effective relation between the pendulous device and rudder by movement of said lever.

25. In an aeroplane, a rudder, a master gtwernor for controlling said rudder, said master governor being in turn controlled by said rudder, a manually operated device, means rendered operative by movement of said device for removing said master governor from the control of said rudder and means for changing the efiective relation between said master governor and rudder upon further movement of said device.

26. In a dirigible device, the combination with a rudder, of an automatic control device therefor, a manual control device therefor, and means brought into action by the initial actuation of said manual device for rendering inoperative said automatic device.

27. In a dirigib'le device, the combination with a rudder, of an automatic control device therefor, a manual control device therefor, and means brought into action by the initial actuation of said manual device for rendering inoperative said automatic device and by continued movement thereof for actuating said rudder from' said manual device.

28. The combination with a gyroscope, of a control member connected thereto, an independently mounted cooperating control member, releasable means for turning'said second member, and yielding means for normally restoring said second member to a predetermined position.

29. The combination with a gyroscope, of a control member connected thereto, an independently mounted cooperating control member, releasable means for a rudder controlled by the relative movement of said members, a follow-up connection between the rudder and the second member, a releasable means in said connections for disconnecting .said connection from the member, and means for restoring said member to a predetermined position.

In testimony whereof I have affixed my signature.

LAWRENCE B. SPFLRRY. 

